After a certain number of layers are wound upon the lapping cylinder, which is called plying, or doubling, the machine is stopped, and the lap broken off and removed to the finisher, which has a carding cylinder, doffer, and comb, similar to the breaker; but instead of the wool, as it comes from the comb, passing round a lapping cylinder, it is drawn through a conical vessel by a pair of rollers, which compress it, and deliver it in thin slivers or bands into tin cans; these, when full, are removed to the draw frame, which is represented in the following diagram.

The draw frame contains several heads of rollers, each head composed of a pair of feeding rollers a a, and a pair of draw rollers b b; the upper roller in each pair is covered with leather, or some other elastic substance, and the lower pair is formed of metal, and fluted. The ends of the slivers contained in the cans c c are passed through the leader d, and brought under the rollers a a and b b. If, now, we suppose the rollers b b to travel four times as fast as the feed rollers a a, or to have a draught of four, as it is termed, the slivers will be drawn out to four times their original length. The slivers are united by passing through a conical ring, and conducted by a pair of rollers f f, (which do not draw or extend the cotton,) into another can g; and if we suppose four ends to be thus united, the sliver will be of the same thickness as the original sliver, but of four times the length. This operation being repeated through several other heads on the same frame, the fibres of the cotton are laid nearly parallel, the sliver becomes more uniform, and is then ready to be carried to the roving frame, in which, besides being reduced, it receives a slight degree of twist.

Roving frames have been variously constructed, but the form most approved and in most general use at the present day is what is termed the spindle and flyer roving frame, represented by the annexed diagram, a a, b b, are draw rollers, between which the sliver is conducted from the cam c, and reduced according to the draught of the rollers; d d is the flyer fixed upon the top of the spindle e, which is put in motion by a band passing over the wheel f. The rollers deliver the reduced sliver to the flyers on the top of the spindles, where it passes through an eye g, and thence proceeds down one of the legs of the flyer (which is made tubular for that purpose,) to the bobbin h, placed loosely on the spindle c, and supported on the rail. The tube of the flyer running swiftly round the bobbin, lays the roving (which thus acquires a t\vist) on the bobbin as fast as the rollers deliver it; and in order to cover the surface of the bobbin with regularity, the rail i is made to ascend and descend alternately with a slow motion.

The bobbin, it will be observed, is dragged round by the flyers, and but for the friction of the surface on which it rests, would move as fast as the flyers; but in this case it would take up no roving, for the quantity taken up will depend upon the difference between the speed of the flyer and the bobbin. A slight degree of friction is then necessary to give the bobbin a slow motion, but as the bobbin becomes full, the weight increases the friction, and consequently would retard the motion still further if it were only dragged round by the flyer; and as it is requisite that the bobbin should always take up the same quantity of roving, its motion is regulated so as to take up the roving exactly as fast as it is delivered from the rollers. The mechanism by which this is accomplished varies in different mills; the following is one of the most approved methods. Two conical barrels are placed opposite each other, the large end of the one fronting the small end of the other. One of these barrels moving uniformly turns the other barrel, by means of an endless strap, which, by being shifted towards either extremity, varies the speed of the other barrel.

The belt or strap remains equally tight in every part of the barrels, for the diameter of the one increases in exactly the same proportion as that of the other diminishes. From the second barrel motion is conveyed to pulleys k resting on the bearer or rail i, and having the spindles passing through the centre of each; the bobbins rest on those pulleys, and are carried round with them. The rovings are next carried to the spinning frame. The spinning frame is similar in its operation to the roving frame, except that it has generally three sets of drawing rollers, and from the greater strength which the thread has acquired, no machinery is requisite to regulate its motion; it is therefore dragged round by the flyers. The bobbins, when taken off the spindles filled with water twist for warps, are carried to be reeled. The reel is composed of six rails, in front of which the bobbins are ranged on pins, in a board extending the whole length of the reel. The dimensions of the reel are such as that it requires exactly 11/2 yard to go round it; the thread from the bobbins, after passing between several wires, to give a proper degree of tension, is made fast to one of the rails, and the wheel set in motion.

After eighty revolutions (one lay) a bell or click strikes, the reel is stopped, and the lays are tied with pieces of thread to keep them distinct. Seven lays form a hank. When the hanks are completed they are taken off the reel, for which purpose one of the rails is hinged, which permits it to be folded inward, and the hank being slided to one end of the reel, the reel is lifted off its bearing, and the hanks are taken off.

It now remains to describe the ope-ration of mule spinning. The preparation is similar to that of water spinning; but previously to the rovings receiving their last reduction on the spinning frame, they undergo a process called stretching. The stretching frame nearly resembling the mule, except in being of larger dimensions: we shall proceed to describe the latter, by means of the annexed diagram, a represents a roving placed in a frame behind the drawing rollers c d e. After passing between the rollers, the reduced roving goes on to the spindle f, which are like those of the common jenny, and have neither bobbins nor flyers. The spindles are placed in a reclining position, and supported on a carriage g. The machine being put in motion, the carriage recedes as fast as the rollers deliver the rovings, the spindles at the same time revolving rapidly, giving sufficient twist to the yard to bear stretching. After the rollers have delivered a certain length (a yard, for example,) of yarn thus imperfectly twisted, they stop, but the carriage continues to recede half a yard further, for example, and the spindles continue to revolve. The yarn is thus stretched, and forms a fair and even thread.